Herbicidal sulfonylureas, their preparation and use

ABSTRACT

Sulfonylureas of the general formula I                    
     where 
     R 1  is a methyl or ethyl group; 
     R 2  is C 1 -C 3 -alkoxycarbonyl, a C 1 -C 2 -alkyl group which carries 1 to 5 fluorine atoms, methylsulfonyl, dimethylaminosulfonyl, thiomethyl, methylsulfinyl, methylsulfonyloxy, trifluoromethoxy, difluoromethoxy, difluorochloromethoxy, difluorochloromethyl or nitro; 
     R 3  is hydrogen, methyl, methoxy, ethoxy, fluorine, chlorine or thiomethyl; 
     W is hydrogen or chlorine and 
     Z is CH or N 
     and their agriculturally utilizable salts are described.

This is a Divisional application of application Ser. No. 09/517,112,filed on Mar. 7, 2000 (allowed), which is a Divisional application ofapplication Ser. No. 09/002,836, filed on Jan. 5, 1998 (now U.S. Pat.No. 6,043,196), which is a Continuation application of application Ser.No. 08/433,521, filed on May 12, 1995 (abandoned), as a National StageApplication under 35 U.S.C. 371, based on International Application No.PCT/EP 93/03,038, filed on Oct. 30, 1993.

The present invention relates to sulfonylureas of the general 5 formulaI

where

R¹ is a methyl or ethyl group;

R² is C₁-C₃-alkoxycarbonyl, a C₁-C₂-alkyl group which carries 1 to 5fluorine atoms, methylsulfonyl, dimethylaminosulfonyl, thiomethyl,methylsulfinyl, methylsulfonyloxy, trifluoromethoxy, difluoromethoxy,difluorochloromethoxy, difluorochloromethyl or nitro;

R³ is hydrogen, methyl, methoxy, ethoxy, fluorine, chlorine orthiomethyl;

W is hydrogen or chlorine and

Z is CH or N

and their agriculturally utilizable salts.

In U.S. Pat. No. 4,120,691, the nearest structures described are thetriazine compound A and the pyrimidine derivative B (cf. also U.S. Pat.No. 4,169,719).

In EP-A 48 808, sulfonylureas D having a substituent in the aromaticmoiety are described.

Z=CH or N

In EP-A 48 143, two N-methylated sulfonylureas E are shown withoutcloser characterization.

Z=CH or N

EP-A 388 873 covers benzoic acid esters of the structure F.

R=CH₃ or C₂H₅

In U.S. Pat. No. 4,310,346, sulfonamides of the type G are listed.

Z=CH or N

German Laid-Open Application DE-OS 40 38 430 (WO 92/09608) describestrifluoromethyl-substituted triazines of type H.

R=halogen, CF₃, alkylsulfonyl or O(CH₂)₂OCH₃

EP-A 120 814 mentions the compound J without details of physical data.

It is an object of the present invention to synthesize sulfonylureaswhich, compared with the known representatives of this class ofherbicide, have improved properties and are particularly distinguishedby high selectivity in sensitive crops.

We have now found that this object can be achieved by the sulfonylureasof the formula I defined at the outset.

In the formula I, C₁-C₃-alkoxycarbonyl is methoxycarbonyl,ethoxycarbonyl, n-propoxycarbonyl or isopropoxycarbonyl and aC₁-C₂-alkyl group which carries 1 to 5 fluorine atoms is methyl,substituted by 1 to 3 fluorine atoms, or ethyl, substituted by 1 to 5fluorine atoms, eg. trifluoromethyl, difluoromethyl,2,2,2-trifluoroethyl or 1,1,2,2-tetrafluoroethyl.

Sulfonylureas of the formula I are particularly preferred in which R² ismethoxycarbonyl, trifluoromethyl, dimethylaminosulfonyl,trifluoromethoxy, difluoromethoxy or methylsulfonyl, and alsosulfonylureas having a triazine substituent (Z=N). Compounds I withdifluoromethyl substitution of hetero atoms (W=H) are additionallyparticularly important.

The sulfonylureas of the formula I according to the invention areaccessible by various routes which are described in the literature. Byway of example, particularly advantageous routes (A-C) may beillustrated in greater detail in the following.

A:

A sulfonyl isocyanate II is reacted in a manner known per se (EP-A-162723) with approximately the stoichiometric amount of a2-amino-1,3,5-triazine or 2-aminopyrimidine derivative III at from 9 to120° C., preferably from 10 to 100° C. The reaction can be carried outcontinuously under normal pressure or under pressure (up to 50 bar),preferably at from 1 to 5 bar.

Inert solvents and diluents are expediently used for the reactions underthe respective reaction conditions. Suitable solvents are, for example,halohydrocarbons, in particular chlorohydrocarbons, eg.tetrachloroethylene, 1,1,1,2- or 1,1,2,2-tetrachloroethane,dichloropropane, methylene chloride, dichlorobutane, chloroform,chloronaphthalene, dichloronaphthalene, carbon tetrachloride, 1,1,1- or1,1,2-trifluoroethane, trichloroethylene, pentachloroethane, o-, m- orp-difluorobenzene, 1,2-dichloroethane, 1,1-dichloroethane,1,2-cis-dichloroethylene, chlorobenzene, fluorobenzene, bromobenzene oriodobenzene, o-, m- or p-dichlorobenzene, o-, p- or m-dibromobenzene,o-, m- or p-chlorotoluene, 1,2,4-trifluorobenzene; ethers, eg. ethylpropyl ether, methyl tert-butyl ether, n-butyl ethyl ether, di-n-butylether, diisobutyl ether, diisoamyl ether, diisopropyl ether, anisole,phenetole, cyclohexyl methyl ether, diethyl ether, ethylene glycoldimethyl ether, tetrahydrofuran, dioxane, thioanisole orβ,β′-dichlorodiethyl ether, nitrohydrocarbons such as nitromethane,nitroethane, nitrobenzene, o-, m- or p-chloronitrobenzene oro-nitrotoluene; nitriles such as acetonitrile, butyronitrile,isobutyronitrile, benzonitrile or m-chlorobenzonitrile; aliphatic orcycloaliphatic hydrocarbons, eg. heptane, pinane, nonane, or o-, m- orp-cymene, benzene fractions within a boiling point range from 70 to 190°C., cyclohexane, methylcyclohexane, decalin, petroleum ether, hexane,naphtha, 2,2,4-trimethylpentane, 2,2,3-trimethylpentane,2,3,3-trimethylpentane or octane; esters, eg. ethyl acetate, ethylacetoacetate or isobutyl acetate; amides, eg. formamide, methylformamideor dimethylformamide; ketones, eg. acetone or methyl ethyl ketone, andsuitable mixtures. The solvent is expediently used in an amount of from100 to 2000% by weight, preferably from 200 to 700% by weight, based onthe starting substance II.

The compound II required for the reaction is in general employed inapproximately equimolar amounts (using an excess or deficit of eg. 0 to20%, based on the respective starting substance III). The startingsubstance III can be introduced in one of the diluents mentioned and thestarting substance II then added.

The process for preparing the novel compounds is expediently carriedout, however, such that the starting substance II is introduced, ifappropriate in one of the abovementioned diluents, and the startingsubstance III is then added.

To complete the reaction, the mixture is subsequently stirred after theaddition of the components for a further 20 minutes to 24 hours at from0 to 120° C., preferably from 10 to 100° C.

A reaction accelerator which can be used is advantageously a tertiaryamine, eg. pyridine, α, β or γ-picoline, 2,4- or 2,6-lutidine,2,4,6-collidine, p-dimethylaminopyridine, trimethylamine, triethylamine,tri(n-propyl)amine, 1,4-diaza[2.2.2]bicyclooctane [DABCO] or1,8-diazabicyclo[5.4.0]undec-7-ene in an amount of from 0.01 to 1 molper mole of starting substance II.

The final substance I is isolated from the reaction mixture in acustomary manner, eg. by removal of solvent by distillation or directlyby filtering off with suction. The residue which remains canadditionally be washed with water or dilute acid to remove basicimpurities. However, the residue can also be dissolved in awater-immiscible solvent and washed as described. The desired finalsubstances are obtained here in pure form. If necessary they can bepurified by recrystallization, stirring in an organic solvent whichtakes up the impurities or chromatography.

Preferably, this reaction is carried out in acetonitrile, methyltert-butyl ether, toluene or methylene chloride in the presence of from0 to 100 mol equivalents, preferably from 0 to 50 mol equivalents, of atertiary amine such as 1,4-diaza-bicyclo[2.2.2]octane or triethylamine.

B:

A sulfonamide of the formula IV is reacted in a manner known per se(EP-A 141 777 or EP-A 101 670) in an inert organic solvent withapproximately the stoichiometric amount of a phenyl carbamate V and from0 to 120° C., preferably from 20 to 100° C. The reaction can be carriedout continuously or batchwise at normal pressure or under pressure (upto 50 bar), preferably at from 1 to 5 bar.

Bases such as tertiary amines can be added here which accelerate thereaction and improve the product quality. Suitable bases for thispurpose are those indicated under A, in particular triethylamine,2,4,6-collidine, 1,4-diazabicyclo[2.2.2]octane [DABCO] or1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), in an amount of from 0.01 to 1mol per mole of starting substance IV.

The solvents or diluents expediently used are those indicated under A.

The solvent is used in an amount of from 100 to 2000% by weight,preferably from 200 to 700% by weight, based on the starting materialIV.

The compound IV required for the reaction is in general employed inapproximately equimolar amounts (using an excess or deficit of eg. from0 to 20%, based on the respective starting substances V). The startingsubstance V can be introduced into one of the abovementioned diluentsand the starting substance IV then added.

However, the starting substance IV can also be introduced into one ofthe solvents mentioned and the carbamate V then added. In both cases oneof the bases mentioned can be added as a catalyst before or during thereaction.

To complete the reaction, the mixture is subsequently stirred after theaddition of the components for a further 20 minutes to 24 hours at from0 to 120° C., preferably from 10 to 100° C., in particular from 20 to80° C.

The sulfonylureas of the formula I are isolated from the reactionmixture using the customary methods, such as described under A.

C:

A sulfonamide of the formula IV is reacted in a manner known per se(EP-A 234 352) in an inert organic solvent with approximately thestoichiometric amount of an isocyanate VI at from 0 to 150° C.,preferably from 10 to 100° C. The reaction can be carried outcontinuously or batchwise at normal pressure or under pressure (up to 50bar), preferably at from 1 to 5 bar.

Before or during the reaction, bases such as tertiary amines can beadded here which accelerate the reaction and improve the productquality. Suitable bases for this purpose are those indicated under A, inparticular triethylamine or 2,4,6-collidine, in an amount of from 0.01to 1 mol per mole of starting substance IV.

The solvents used are expediently those indicated under A. The solventis employed in an amount of from 100 to 2000% by weight, preferably of200 to 700% by weight, based on the starting material IV.

The compound IV required for the reaction is in general employed inapproximately equimolar amounts (using an excess or deficit of eg. from0 to 20%, based on the starting materials VI). The starting substance VIcan be initially introduced into one of the diluents mentioned and thestarting substance IV then added. However, the sulfonamide can also beinitially introduced and the isocyanate VI then added.

To complete the reaction, the mixture is stirred after the addition ofthe components for a further 20 minutes to 24 hours at from 0 to 120°C., preferably from 10 to 100° C., in particular from 20 to 80° C. Thefinal product I can be obtained from the reaction mixture in thecustomary manner, as described under A:.

The sulfonyl isocyanates of the formula II required as startingsubstances can be obtained from the corresponding sulfonamides byphosgenation in a manner known per se (Houben-Weyl 11/2 (1985) 1106,U.S. Pat. No. 4,379,769) or by reaction of the sulfonamides withchlorosulfonyl isocyanate (DE-A 31 32 944).

Carbamates of the formula V are accessible by or in a similar manner toknown reactions (eg. EP-A 101 670); however, they can also be preparedfrom the corresponding isocyanates VI by reaction with phenol.

The isocyanates of the formula VI are obtained from the amines of theformula III by treatment with oxalyl chloride or phosgene (in a similarmanner to Angew. Chem. 83 (1971) 407, EP-A 388 873).

The sulfonamides can be obtained by reaction of the correspondingsulfonyl chlorides with ammonia (Houben-Weyl, Methoden der organischenChemie (Methods of organic chemistry), Volume 9 (1955) 605). Thesulfonyl chlorides are obtained by Meerwein reaction (diazotization ofsuitable amines and copper salt-catalyzed sulfochlorination).2-Amino-4-chlorodifluoromethyl-6-methoxy-1,3,5-triazine and2-amino-4-difluoromethyl-6-methoxy-1,3,5-triazine can be synthesized asillustrated in the preparation example. The corresponding6-ethoxy-substituted 1,3,5-triazines can be prepared in a similarmanner.

The corresponding pyrimidines of the general formula III are accessibleby the following sequence:

Corresponding reactions are well known (D. J. Brown in “The Chemistry ofHeterocyclic Compounds”, Interscience Publishers, New York, London, Vol.14, Heterocycl. Chem. 20 (1983) 219).

The compounds I can be present in the form of their agriculturallyutilizable salts, where in general the nature of the salt does notmatter. Customarily, the salts of those bases will be suitable which donot adversely affect the herbicidal action of I.

The salts of the compounds I are accessible in a manner known per se(EP-A-304 282, U.S. Pat. No. 4,599,412). They are obtained bydeprotonation of the corresponding sulfonylureas I in water or an inertorganic solvent at from −80° C. to 120° C., preferably from 0° C. to 60°C., in the presence of a base.

Suitable bases are, for example, alkali metal or alkaline earth metalhydroxides, hydrides, oxides or alkoxides such as sodium, potassium andlithium hydroxide, sodium methoxide, ethoxide and tert-butoxide, sodiumand calcium hydride and calcium oxide. Salts of transition metals,preferably manganese, copper, zinc and iron salts and also the ammoniumsalts which can carry one to three C₁-C₄-alkyl or hydroxy-C₁-C₄-alkylsubstituents and/or a phenyl or benzyl substituent, preferablydiisopropylammonium, tetramethylammonium, tetrabutylammonium,trimethylbenzylammonium and trimethyl(2-hydroxyethyl)ammonium salts, thephosphonium salts, the sulfonium salts, preferablytri-(C₁-C₄)-alkylsulfonium salts, and the sulfoxonium salts, preferablytri-(C₁-C₄)-alkylsulfoxonium salts can also be employed as basic salts.

In addition to water, suitable solvents, for example, are also alcoholssuch as methanol, ethanol and tert-butanol, ethers such astetrahydrofuran and dioxane, acetonitrile, dimethylformamide, ketonessuch as acetone and methyl ethyl ketone and also halogenatedhydrocarbons.

Deprotonation can be carried out at normal pressure or at pressures ofup to 50 bar, preferably at normal pressure up to an excess pressure of5 bar.

The compounds I or the herbicidal compositions containing them and theirenvironmentally tolerable salts of alkali metals and alkaline earthmetals can very effectively control weeds in crops such as wheat, riceand maize without damaging the crop plants, an effect which occursespecially even at low application rates. They can be applied byspraying, atomizing, dusting, broadcasting or watering in the form ofdirectly sprayable solutions, powders or suspensions, evenhigh-percentage aqueous, oily or other suspensions, or dispersions,emulsions, oil dispersions, pastes, dusting compositions, broadcastingcompositions or granules. The application forms depend on the intendeduse; in each case they should if possible guarantee the finestdispersion of the active compounds according to the invention.

The compounds I are generally suitable for preparing directly sprayablesolutions, emulsions, pastes or oil dispersions. Suitable inertadditives are, inter alia, mineral oil fractions of medium to highboiling point, such as kerosene or diesel oil, and also coal tar oilsand oils of vegetable or animal origin, aliphatic, cyclic and aromatichydrocarbons, eg. toluene, xylene, paraffin, tetrahydronaphthalene,alkylated naphthalenes or their derivatives, methanol, ethanol,propanol, butanol, cyclohexanol, cyclohexanone, chlorobenzene,isophorone or strongly polar solvents, such as N,N-dimethylformamide,dimethyl sulfoxide, N-methylpyrrolidone or water.

Aqueous application forms can be prepared from emulsion concentrates,dispersions, pastes, wettable powders or water-dispersible granules byaddition of water. To prepare emulsions, pastes or oil dispersions, thesubstrates as such or dissolved in an oil or solvent can be homogenizedin water by means of wetting agents, adhesives, dispersants oremulsifiers. However, concentrates consisting of active substance,wetting agent, adhesive, dispersant or emulsifier and possibly solventor oil can be prepared, which are suitable for dilution with water.

Suitable surface-active substances are the alkali metal, alkaline earthmetal and ammonium salts of aromatic sulfonic acids, eg. lignosulfonic,phenolsulfonic, naphthalenesulfonic and dibutylnaphthalenesulfonic acid,and of fatty acids, alkyl- and alkylrylsulfonates, alkyl-, lauryl etherand fatty alcohol sulfates, as well as salts of sulfated hexa-, hepta-and octadecanols, and also of fatty alcohol glycol ethers, condensationproducts of sulfonated naphthaline and its derivatives withformaldehyde, condensation products of naphthalene or ofnaphthalenesulfonic acids with phenol and formaldehyde, polyoxyethyleneoctylphenol ether, ethoxylated isooctyl-, octyl- or nonylphenol,alkylphenol or tributylphenyl polyglycol ethers, alkylaryl polyetheralcohols, isotridecyl alcohol, fatty alcohol/ethylene oxide condensates,ethoxylated castor oil, polyoxyethylene or polyoxypropylene alkylethers, lauryl alcohol polyglycol ether acetate, sorbitol esters,lignin-sulfite waste liquors or methylcellulose.

Powder, broadcasting and dusting compositions can be prepared by mixingor joint grinding of the active substances with a solid carrier.

Granules, eg. coated, impregnated and homogeneous granules can beprepared by binding the active compounds to solid carriers. Solidcarriers are mineral earths such as silicic acids, silica gels,silicates, talc, kaolin, limestone, lime, chalk, bole, loess, clay,dolomite, diatomaceous earth, calcium sulfate and magnesium sulfate,magnesium oxide, ground synthetic materials, fertilizers, such asammonium sulfate, ammonium phosphate, ammonium nitrate, ureas andvegatable products, such as cereal meal, tree bark meal, wood meal andnut shell meal, cellulose powder or other solid carriers.

The formulations in general contain from 0.1 to 95% by weight,preferably from 0.5 to 90% by weight, of active compound. The activecompounds are employed here in a purity of from 90 to 100%, preferablyfrom 95 to 100% (according to NMR spectrum).

EXAMPLES OF SUCH PREPARATIONS ARE

I

20 parts by weight of the compound No. 1.01 are dissolved in a mixturewhich consists of 80 parts by weight of alkylated benzene, 10 parts byweight of the additional product of from 8 to 10 mol of ethylene oxideto 1 mol of oleic acid N-monoethanolamide and 5 parts by weight of theaddition product of 40 mol of ethylene oxide to 1 mol of castor oil. Bypouring out the solution and finely dispersing it in 100,000 parts byweight of water, an aqueous dispersion is obtained which contains 0.02%by weight of the active compound.

II

20 parts by weight of the compound No. 1.01 are dissolved in a mixturewhich consists of 40 parts by weight of cyclohexanone, 30 parts byweight of isobutanol, 20 parts by weight of the additional product of 7mol of ethylene oxide to 1 mol of isooctylphenol and 10 parts by weightof the addition product of 40 mol of ethylene oxide to 1 mol of castoroil. By pouring the solution into and finely dispersing it in 100,000parts by weight of water, an aqueous dispersion is obtained whichcontains 0.02% by weight of the active compound.

III

20 parts by weight of the active compound No. 1.01 are dissolved in amixture which consists of 25 parts by weight of cyclohexanone, 65 partsby weight of a mineral oil fraction of boiling point 210 to 280° C. and10 parts by weight of the addition product of 40 mol of ethylene oxideto 1 mol of castor oil. By pouring the solution into and finelydispersing it in 100,000 parts by weight of water, an aqueous dispersionis obtained which contains 0.02% by weight of the active compound.

IV

20 parts by weight of the active compound No. 1.01 are well mixed with 3parts by weight of the sodium salt of diisobutylnaphthalene-α-sulfonicacid, 17 parts by weight of the sodium salt of a lignosulfonic acid froma sulfite waste liquor and 60 parts by weight of powdered silica gel andthe mixture is ground in a hammer mill. By finely dispersing it in20,000 parts by weight of water, a spray liquor is obtained whichcontains 0.1% by weight of the active compound.

V

3 parts by weight of the active compound No. 1.01 are mixed with 97parts by weight of finely divided kaolin. In this manner, a dustingcomposition is obtained which contains 3% by weight of the activecompound.

VI

20 parts by weight of the active compound No. 1.01 are intimately mixedwith 2 parts by weight of calcium salt of dodecylbenzenesulfonic acid, 8parts by weight of fatty alcohol polyglycol ether, 2 parts by weight ofsodium salt of a phenol/urea/formaldehyde condensate and 68 parts byweight of a paraffinic mineral oil. A stable oily dispersion isobtained.

The application of the herbicidal compositions or of the activecompounds can be carried out pre-emergence or post-emergence. If theactive compounds are less tolerable for certain crop plants, applicationtechniques can be used in which the herbicidal compositions are sprayedwith the aid of the spray equipment such that the leaves of thesensitive crop plants are not affected if possible, while the activecompounds reach the leaves of undesired plants growing under them or theuncovered soil surface (post-directed, lay-by).

The application rates of active compound, depending on the target to becontrolled, time of year, target plants and stage of growth, are from0.001 to 1.0, preferably from 0.01 to 0.5, kg/ha of active substance(a.S.).

In consideration of the variety of application methods, thesulfonylureas I or compositions containing them can also be employed ina further number of crop plants for eliminating undesired plants.Suitable crops are, for example, the following:

Allium cepa, Ananas comosus, Arachis hypogaea, Asparagus officinalis,Beta vulgaris spp. altissima, Beta vulgaris spp. rapa, Brassica napusvar. napus, Brassica napus var. napobrassica, Brassica rapa var.silvestris, Camellia sinensis, Carthamus tinctorius, Caryaillinoinensis, Citrus limon, citrus sinensis, Coffea arabica (Coffeacanephora, Coffea liberica), Cucumis sativus, Cynodon dactylon, Daucuscarota, Elaeis guineensis, Fragaria vesca, Glycine max, Gossypiumhirsutum (Gossypium arboreum, Gossypium herbaceum, Gossypiumvitifolium), Helianthus annuus, Hevea brasiliensis, Hordeum vulgare,Humulus lupulus, Ipomoea batatas, Juglans regia, Lens culinaris, Linumusitatissimum, Lycopersicon lycopersicum, Malus spp., Manihot esculenta,Medicago sativa, Musa spp., Nicotiana tabacum (N. rustica), Oleaeuropaea, Oryza sativa, Phaseolus lunatus, Phaseolus vulgaris, Piceaabies, Pinus spp., Pisum sativum, Prunus avium, Prunus persica, Pyruscommunis, Ribes sylvestre, Ricinus communis, Saccharum officinarum,Secale cereale, Solanum tuberosum, Sorghum bicolor (S. vulgare),Theobroma cacao, Trifolium pratense, Triticum aestivum, Triticum durum,Vicia faba, Vitis vinifera and Zea mays.

To widen the spectrum of action and to achieve synergistic effects, thesubstituted sulfonylureas of the formula I can be mixed with numerousrepresentatives of other herbicidal or growth-regulating active compoundgroups and applied together. For example, suitable mixture componentsare diazines, 4H-3,1-benzoxazine derivatives, benzothiodiazinones,2,6-dinitroanilines, N-phenylcarbamates, thiocarbamates, halocarboxylicacids, triazines, amides, ureas, diphenyl ethers, triazinones, uracils,benzofuran derivatives, cyclohexane-1,3-dione derivatives,quinolinecarboxylic acid derivatives, phenyloxy- orheteroaryloxyphenylpropionic acids and their salts, esters and amidesand others.

It may additionally be useful to apply the compounds of the formula I ontheir own or together in combination with other herbicides andadditionally with other crop protection compositions, for example withcompositions for controlling pests or phytopathogenic fungi or bacteria.Also of interest is the miscibility with mineral salt solutions whichare employed for eliminating nutritional and trace element deficiencies.Non-phytotoxic oils and oil concentrates can also be added.

Examples of the synthesis of the compounds I are given below.

Preparation of the Starting Substances2-Amino-4-chlorodifluoromethyl-6-methoxy-1,3,5-triazine

a) 2-Amino-4-chlorodifluoromethyl-6-thiomethyl-1,3,5-triazine

A suspension of 18.5 g of N-amidinothiourea (adduct withN-methyl-2-pyrrolidone) (85 mmol) in 90 ml of methanol was treated with10.7 g of dimethyl sulfate (85 mmol) and stirred at from 30 to 40° C.for 3 h. 25 g of methyl chlorodifluoroacetate (0.17 mol) was addeddropwise to this solution at 0° C., followed by 30.6 g of a 30% byweight solution of sodium methoxide in methanol (0.17 mol). The coolingwas removed and the mixture was subsequently stirred at 25° C. for 16 h.The solvent was removed at 40° C., the residue was stirred with 400 mlof water, and the product was filtered off with suction and dried at 40°C. in a water-jet vacuum. The crude product (m.p. 118° C.) was employedin Stage b) without purification (¹H-NMR spectrum (250 MHz, CDCl₃, int.TMS, δ (ppm): 6.74 br (1H); 5.94 br (1H); 2.54 s (3H)).

b) 2-Amino-4-chlorodifluoromethyl-6-methoxy-1,3,5-triazine

A solution of 19 g of crude product (84 mmol) from Stage a) in 100 ml ofmethanol was treated dropwise at 0° C. with 16.2 g of a 30% strength byweight solution of sodium methoxide in methanol (90 mmol). The coolingwas removed and the mixture was subsequently stirred at 25° C. for 16 h.A pH of 6 was set by addition of 4N HCl, the solvent was removed at 40°C. in a water-jet vacuum and the residue was stirred with 400 ml ofwater. The product was filtered off with suction, washed with water anddried at 40° C. in a water-jet vacuum.

13.9 g of the title compound (79% of theory) were thus obtained of m.p.130° C. (¹H-NMR spectrum (250 MHz, CDCl₃, int. TMS, δ (ppm): 6.78 br(1H); 6.08 br (1H); 4.03 s (3H)).

2-Amino-6-difluoromethyl-6-methoxy-1,3,5-triazine

a) 2-Amino-4-difluoromethyl-6-trichloromethyl-1,3,5-triazine

A solution of 70.1 g of difluoroacetic anhydride (0.4 mol) in 200 ml ofdiethyl ether was treated in portions with 40.7 g ofN-(trichloroacetamidino)guanidine (0.2 mol) at 0° C. The mixture wasstirred at from 20 to 25° C. for 3 hours. The volatile fractions wereremoved at 40° C. in a water-jet vacuum, the residue was partitionedbetween 400 ml of water and 200 ml of methylene chloride and themethylene chloride phase was carefully neutralized with dilute sodiumhydroxide solution (2% strength by weight). After separating off anddrying the methylene chloride phase over Na₂SO₄, the solvent wasdistilled off at 40° C. in a water-jet vacuum. 39.6 g (0.15 mol) (75% oftheory) of a spectroscopically pure crude product were thus obtained,which can thus be employed in the subsequent reaction (Stage b) withoutpurification.

¹H-NMR spectrum (270 MHz, d₆-DMSO, int. TMS, δ (ppm): 8.80 br (2H); 6.78tr (1H;J_(H-F) 162 Hz)).

b) 2-Amino-4-difluoromethyl-6-methoxy-1,3,5-triazine

A solution of 22.5 g of crude product (85 mmol) from Stage a) in 100 mlof methanol was treated dropwise at 0° C. with 1.6 g of a 30% strengthby weight solution of sodium methoxide in methanol (9 mmol). The coolingwas removed and the mixture was subsequently stirred at 25° C. for 16hours. After addition of a further 1.6 g of a 30% strength by weightsolution of sodium methoxide in methanol (9 mmol), the mixture wassubsequently stirred at 25° C. for 3 hours. A pH of 7 was set byaddition of 3N hydrochloric acid, the solvent was removed in a water-jetvacuum at 40° C. and the residue was vigorously stirred with 400 ml ofwater. The product was filtered off with suction, washed with water anddried at 40° C. in a water-jet vacuum.

10.7 g of the title compound (0.61 mol; 71% of theory) were thusobtained. ¹H-NMR spectrum (270 MHz, d₆-DMSO, int. TMS, δ (ppm): 8.02,7.94 br (2H); 6.55 tr (1H;J_(H-F) 162 Hz); 3.90 s (3H)).

Preparation of the Sulfonylureas of the Formula I Example 1.03

Methyl [2-[[(4-chlorodifluoromethyl-6-methoxy-1,3,5-triazin-2-yl)-aminocarbonyl]aminosulfonyl]benzoate

A solution of 4.2 g of2-amino-4-chlorodifluoromethyl-6-methoxy-1,3,5-triazine (20 mmol) in 20ml of methylene chloride was treated at 25° C. with a solution of 4.8 gof 2-methoxycarbonylbenzenesulfonyl isocyanate (20 mmol) in 5 ml ofmethylene chlor-ide. The mixture was stirred at 25° C. for 16 h, thesolvent was removed in a water-jet vacuum at 40° C. and the solidresidue was stirred with 100 ml of a hexane/diethyl ether mixture (v:v,1:1). The separated product was filtered off with suction, washed with alittle ether and dried. The title compound (3.2 g, 35% of theory) ofm.p. 174 to 175° C. was obtained by recrystallizing from methanol/water.

Example 1.05

N-[(4-Chlorodifluoromethyl-6-methoxy-1,3,5-triazin-2-yl)aminocarbonyl]-2-nitrobenzenesulfonamide.

A solution of 4.2 g of2-amino-4-chlorodifluoromethyl-6-methoxy-1,3,5-triazine (20 mmol) in 20ml of methylene chloride was treated at 25° C. with a solution of 4.6 gof 2-nitrobenzenesulfonyl isocyanate (20 mmol) in 5 ml of methylenechloride. The mixture was subsequently stirred at 25° C. for 16 h, andthe deposited product was filtered off with suction, washed with alittle ether and dried at 40° C. in a water-jet vacuum. 3.1 g of thetitle compound (35% of theory) of m.p. 181° C. were thus obtained.

Example 1.06

Sodium N-[(4-chlorodifluoromethyl-6-methoxy-1,3,5-triazin-2-yl)aminocarbonyl]-2-nitrobenzenesulfonamide

A suspension of 1.5 g ofN-[(4-chlorodifluoromethyl-6-methoxy-1,3,5-triazin-2-yl)aminocarbonyl]-2-nitrobenzenesulfonamide(3.4 mmol) in 10 ml of methanol was treated at 25° C. with 0.62 g of a30% strength by weight solution of sodium methoxide (3.4 mmol) inmethanol, whereupon dissolution occurred. The mixture was subsequentlystirred at 25° C. for 30 min and the volatile fractions were removed at40° C. in a water-jet vacuum. The title compound was thus obtained inquantitative yield with a decomposition point of 169° C.

Example 3.01

2-[ (4-Difluoromethyl-6-methoxy-1,3,5-triazin-2-yl)aminocarbonyl]aminosulfonyl]benzotrifluoride

A solution of 2.65 g of2-amino-4-difluoromethyl-6-methoxy-1,3,5-triazine (15 mmol) in 20 ml ofacetonitrile was treated at 25° C. with 3.7 g of2-trifluoromethylbenzenesulfonyl isocyanate (15 mmol). The mixture wassubsequently stirred at 25° C. for 16 h, the solvent was removed in awater-jet vacuum at 40° C. and the solid residue was stirred vigorouslywith 100 ml of diethyl ether. The product was filtered off with suction,washed with a little ether and dried. 4.3 g (10 mmol, 67% of theory) ofthe title compound of m.p. 143-145° C. were obtained.

Example 3.02

Sodium N-[(4-difluoromethyl-6-methoxy-1,3,5-triazin-2-yl)aminocarbonyl]aminosulfonylbenzotrifluoride.

A suspension of 1.3 g of 2-[[(4-difluoromethyl-6-methoxy-1,3,5-triazin-2-yl)aminocarbonyl]aminosulfonyl]benzotrifluoride (3 mmol) in10 ml of methanol was treated at 25° C. with 0.54 g of a 30% strength byweight solution of sodium methoxide (3 mmol) in methanol, whereupondissolution occurred. The mixture was subsequently stirred at 25° C. for30 min and the volatile fractions were removed at 40° C. in a water-jetvacuum. The title compound was thus obtained in quantitative yield witha decomposition point of 189-192° C.

The active compounds mentioned in the following Tables 1 to 4 areobtained by a similar preparative route.

TABLE 1

Active Compound No. R¹ R² R³ M.p. [° C.] 1.01 CH₃ CF₃ H 175-172 1.02 CH₃CF₃ H 192-193 (d)* 1.03 CH₃ CO₂CH₃ H 174-175 1.04 CH₃ CO₂CH₃ H 171 (d)*1.05 CH₃ NO₂ H 181 1.06 CH₃ NO₂ H 169 (d)* 1.07 CH₃ SO₂N(CH₃)₂ H 152-1541.08 CH₃ SO₂N(CH₃)₂ H 125-130 (d)* 1.09 CH₃ SCH₃ 6-SCH₃ >200 1.10 CH₃OSO₂CH₃ H 1.11 CH₃ OSO₂CH₃ H * 1.12 CH₃ OCF₃ H 1.13 CH₃ OCH₃ H * 1.14CH₃ OCF₂H H 1.15 CH₃ OCF₂H H * 1.16 CH₃ SO₂CH₃ H 1.17 CH₃ SO₂CH₃ H *1.18 CH₃ CO₂C₂H₅ H 159-167 1.19 CH₃ CO₂C₂H₅ H * 1.20 CH₃ CO₂iC₃H₇ H 1.21CH₃ CO₂iC₃H₇ H * 1.22 CH₃ CO₂CH₃ 5-OCH₃ 155-160 1.23 CH₃ CO₂CH₃ 5-OCH₃165-170 (d)* *Na salt

The compounds shown below can also be obtained in a similar manner:

or their Na salts, where R³ has the following meanings:

3-methyl, 5-methyl, 6-methyl, 3-thiomethyl, 5-thiomethyl, 6-thiomethyl,3-fluoro, 5-fluoro, 6-fluoro, 3-chloro, 5-chloro, 6-chloro, 3-methoxy,4-methoxy, 5-methoxy, 6-methoxy, 3-ethoxy, 5-ethoxy, 6-ethoxy;

 their Na salts, where R³ has the following meanings:

3-methyl, 5-methyl, 6-methyl, 3-thiomethyl, 5-thiomethyl, 6-thiomethyl,3-fluoro, 5-fluoro, 6-fluoro, 3-chloro, 5-chloro, 6chloro, 3-methoxy,4-methoxy, 5-methoxy, 6-methoxy, 3-ethoxy, 5-ethoxy, 6-ethoxy;

 or their Na salts, where R³ has the following meanings:

3-methyl, 5-methyl, 6-methyl, 3-thiomethyl, 5-thiomethyl, 6-thiomethyl,3-fluoro, 5-fluoro, 6-fluoro, 3-chloro, 5-chloro, 6-chloro, 3-methoxy,4-methoxy, 5-methoxy, 6-methoxy, 3-ethoxy, 5-ethoxy, 6-ethoxy;

 or their Na salts, where R³ has the following meanings:

3-methyl, 5-methyl, 6-methyl, 3-thiomethyl, 5-thiomethyl, 6-thiomethyl,3-fluoro, 5-fluoro, 6-fluoro, 3-chloro, 5-chloro, 6-chloro, 3-methoxy,4-methoxy, 5-methoxy, 6-methoxy, 3-ethoxy, 5-ethoxy, 6-ethoxy;

 or their Na salts, where R³ has the following meanings:

3-methyl, 5-methyl, 6-methyl, 3-thiomethyl, 5-thiomethyl, 6-thiomethyl,3-fluoro, 5-fluoro, 6-fluoro, 3-chloro, 5-chloro, 6-chloro, 3-methoxy,4-methoxy, 5-methoxy, 6-methoxy, 3-ethoxy, 5-ethoxy, 6-ethoxy;

 or their Na salts, where R³ has the following meanings:

3-methyl, 5-methyl, 6-methyl, 3-thiomethyl, 5-thiomethyl, 6-thiomethyl,3-fluoro, 5-fluoro, 6-fluoro, 3-chloro, 5-chloro, 6-chloro, 3-methoxy,4-methoxy, 5-methoxy, 6-methoxy, 3-ethoxy, 5-ethoxy, 6-ethoxy;

 or their Na salts, where R³ has the following meanings:

3-methyl, 5-methyl, 6-methyl, 3-thiomethyl, 5-thiomethyl, 6-thiomethyl,3-fluoro, 5-fluoro, 6-fluoro, 3-chloro, 5-chloro, 6-chloro, 3-methoxy,4-methoxy, 5-methoxy, 6-methoxy, 3-ethoxy, 5-ethoxy, 6-ethoxy.

TABLE 2

Active Compound No. R¹ R² R³ M.p. [° C.] 2.01 CH₃ CF₃ H 2.02 CH₃ CF₃ H *2.03 CH₃ CO₂CH₃ H 2.04 CH₃ CO₂CH₃ H * 2.05 CH₃ NO₂ H 2.06 CH₃ NO₂ H *2.07 CH₃ SO₂N(CH₃)₂ H 2.08 CH₃ SO₂N(CH₃)₂ H * 2.09 CH₃ SCH₃ 6-SCH₃ 2.10CH₃ OSO₂CH₃ H 2.11 CH₃ OSO₂CH₃ H * 2.12 CH₃ OCF₃ H 2.13 CH₃ OCH₃ H *2.14 CH₃ OCF₂H H 2.15 CH₃ OCF₂H H * 2.16 CH₃ SO₂CH₃ H 2.17 CH₃ SO₂CH₃H * 2.18 CH₃ CO₂C₂H₅ H 2.19 CH₃ CO₂C₂H₅ H * 2.20 CH₃ CO₂iC₃H₇ H 2.21 CH₃CO₂iC₃H₇ H * *Na salt

TABLE 3

Active Compound No. R¹ R² R³ M.p. [° C.] 3.01 CH₃ CF₃ H 143-145 3.02 CH₃CF₃ H *189-192 (d) 3.03 CH₃ CO₂CH₃ H 144-146 3.04 CH₃ CO₂CH₃ H *168 (d)3.05 CH₃ NO₂ H 3.06 CH₃ NO₂ H * 3.07 CH₃ SO₂N(CH₃)₂ H 160-162 3.08 CH₃SO₂N(CH₃)₂ H * 3.09 CH₃ SCH₃ 6-SCH₃ 3.10 CH₃ OSO₂CH₃ H 146-148 3.11 CH₃OSO₂CH₃ H * 3.12 CH₃ OCF₃ H 158-161 3.13 CH₃ OCF₃ H *120 (d) 3.14 CH₃OCF₂H H 146-148 3.15 CH₃ OCF₂H H *161 (d) 3.16 CH₃ SO₂CH₃ H 3.17 CH₃SO₂CH₃ H * 3.18 CH₃ CO₂C₂H₅ H 167-169 3.19 CH₃ CO₂C₂H₅ H *158 (d) 3.20CH₃ CO₂iC₃H₇ H 3.21 CH₃ CO₂iC₃H₇ H * *Na salt

TABLE 4

Active Compound No. R¹ R² R³ M.p. [° C.] 4.01 CH₃ CF₃ H 4.02 CH₃ CF₃ H *4.03 CH₃ CO₂CH₃ H 4.04 CH₃ CO₂CH₃ H * 4.05 CH₃ NO₂ H 4.06 CH₃ NO₂ H *4.07 CH₃ SO₂N(CH₃)₂ H 4.08 CH₃ SO₂N(CH₃)₂ H * 4.09 CH₃ SCH₃ 6-SCH₃ 4.10CH₃ OSO₂CH₃ H 4.11 CH₃ OSO₂CH₃ H * 4.12 CH₃ OCF₃ H 4.13 CH₃ OCH₃ H *4.14 CH₃ OCF₂H H 4.15 CH₃ OCF₂H H * 4.16 CH₃ SO₂CH₃ H 4.17 CH₃ SO₂CH₃H * 4.18 CH₃ CO₂C₂H₅ H 4.19 CH₃ CO₂C₂H₅ H * 4.20 CH₃ CO₂iC₃H₇ H 4.21 CH₃CO₂iC₃H₇ H * *Na salt

Use examples:

The herbicidal action of the sulfonylureas of the formula I on thegrowth of the test plants is shown by the following greenhouse tests.

The cultivation containers used were plastic flowerpots containing loamysand with about 3.0% humus as a substrate. The seeds of the test plantswere sown separately according to species.

In the case of pre-emergence treatment, the active compounds suspendedor emulsified in water were applied directly after sowing by means offinely dispersing nozzles. The containers were lightly watered in orderto promote germination and growth and then covered with transparentplastic hoods until the plants had taken root. This covering causes auniform germination of the test plants if this has not been adverselyaffected by the active compounds.

For the purpose of post-emergence treatment, the test plants were firstraised, depending on growth form, to a growth height of from 4 to 15 cmand only then treated with the active compounds suspended or emulsifiedin water. To do this, the test plants were either directly sown andraised in the same containers or they were first raised separately asseed plants and transplanted into the test containers a few days beforethe treatment. The application rate for post-emergence treatment was0.06 kg/ha of a.s. (active substance).

The plants were kept in a species-specific manner at 10-25° C. or 20-35°C. The test period extended over 2 to 4 weeks. During this time theplants were tended and their reaction to the individual treatments wasassessed.

Assessment was carried out on a scale of from 0 to 100. 100 here meansno germination of the plants or complete destruction of at least theabove-ground parts and 0 means no damage or normal course of growth.

The plants used in the greenhouse tests were composed of the followingspecies:

Botanical Name Common Name Abutilon theophrasti Velvetleaf Sinapis albaWhite mustard Zea mays Maize

Using 0.06 kg/ha of a.s. post-emergence, broad-leaved undesired plantscan be very well controlled with Example 1.03, together withsimultaneous outstanding selectivity in the exemplary crop plant maize.

In the following tables, results of biological investigations arecompiled in which the active compound according to the invention Example1.03 was compared with the compound B known from U.S. Pat. No. 4,169,719and the active compound according to the invention No. 3.01 was comparedwith the comparison compound H known from WO 92/09608.

Table I:

Comparison of the herbicidal activity of the exemplary compound No. 1.03with the known comparison compound B on post-emergence application of0.0313 or 0.0156 kg/ha of a.s. respectively in the greenhouse.

Damage [%] Application rate [kg/ha of a.s.] Example 1.03 B Test plants0.0313 0.0156 0.0313 0.0156 Amaranthus retroflexus 100 100 75 70 Galiumaparine 95 75 85 40 Polygonum persicaria 80 80 40 40 Sinapis alba 90 9075 75 Solanum nigrum 90 90 60 60 Veronica spp. 85 75 50 40

Table II:

Comparison of the herbicidal activity of the exemplary compound No. 3.01with the known comparison compound H on post-emergence application of0.063 or 0.0313 kg/ha of a.s. respectively in the greenhouse.

Damage [%] Application rate [kg/ha of a.s.] Example 3.01 H Test plants0.063 0.0313 0.063 0.0313 Alopecurus myosuroides 98 98 40 0 Galiumaparine 95 95 95 95 Ipoinea spp. 98 90 80 80 Sinapis alba 98 98 100 100Triticum aestivum 0 0 0 0

We claim:
 1. A sulfonylurea of formula I

where R¹ is a methyl or ethyl group; R² is C₁-C₃-alkoxycarbonyl, aC₁-C₂-alkyl group which carries 1 to 5 fluorine atoms, methylsulfonyl,dimethylaminosulfonyl, methylthio, methyl sulfoxide, methylsulfonyloxy,trifluoromethoxy, difluoromethoxy, difluorochloromethoxy,difluorochloromethyl or nitro; R³ is hydrogen, methyl, methoxy, ethoxy,fluorine, chlorine or methylthio; W is hydrogen or chlorine, and Z isCH, or an agriculturally utilizable salt thereof.
 2. A sulfonylurea ofthe formula I as claimed in claim 1, where R² is methoxycarbonyl,trifluoromethyl, dimethylaminosulfonyl, trifluoromethoxy,difluoromethoxy or methylsulfonyl.
 3. The sulfonylurea of formula Idefined in claim 1, where W is hydrogen.
 4. A herbicidal compositioncomprising the sulfonylurea of formula I defined in claim 1 or a saltthereof salt and one or more customary carriers.
 5. A process forcontrolling undesired plant growth, which comprises allowing aherbicidally active amount of the sulfonylurea of formula I defined inclaim 1 or of a salt thereof to act on the plants and/or theirenvironment.
 6. The sulfonylurea of formula I defined in claim 1,wherein R¹ is methyl.
 7. The sulfonylurea of formula I defined in claim1, wherein W is chlorine.
 8. The sulfonylurea of formula I defined inclaim 1, wherein R² is trifluoromethyl.
 9. The sulfonylurea of formula Idefined in claim 1, wherein R² is difluoromethoxy.
 10. The sulfonylureaof formula I defined in claim 1, wherein R³ is hydrogen.
 11. Thesulfonylurea of formula I defined in claim 1, wherein R¹ is methyl, R²is trifluoromethyl, R³ is hydrogen and W is chlorine.
 12. Thesulfonylurea of formula I defined in claim 1, wherein R¹ is methyl, R²is CO₂CH₃, R³ is hydrogen and W is chlorine.
 13. The sulfonylurea offormula I defined in claim 1, wherein R¹ is methyl, R² istrifluoromethyl, R³ is hydrogen and W is hydrogen.
 14. The sulfonylureaof formula I defined in claim 1, wherein R¹ is methyl, R² is CO₂CH₃, R³is hydrogen and W is hydrogen.